The present invention relates to a vehicular power window safety device, and more particularly, to a vehicular power window safety device adapted to prevent erroneous operation.
A conventional vehicle is typically provided with a power window regulator for lifting a window glass supported by a door frame motor. There can be a problem, however, in lifting the window glass because injury may occur to occupants, or objects may be damaged by the driving force of the motor when the window glass is raised. This may happen, for example, when a child""s hand or an object is accidentally placed in the upper area of the window adjacent the door frame.
In order to reduce accidents involving the operation of power windows, many countries have enacted regulations and allow sales of vehicles only as long as the vehicles meet the requirements of the concerned regulations. A typical prior art safety device for a power window regulator is designed to reverse the direction of the motor when the window glass encounters an obstruction within a safety space at the top of the window (sometimes referred to as an object occupation space). A sensor, such as a hall sensor, is configured to sense the revolutions of the power window motor. When the window glass encounters an obstruction in the safety space, such as a child""s hand or other object placed through the window, the force of the object resulting from being pressed against the top of the door frame causes the rotation of the motor to slow down. The sensor detects this slow down and immediately causes the motor to reverse its direction.
However, in normal operation of the window, when the window glass is either ascending or descending, conditions may exist that cause increased friction along the window glass running channels. If this occurs, the motion of the window glass may slow down and the sensor erroneously interprets the slow down as an obstruction in the safety space, causing the window motor to improperly reverse directions.
There is therefore a need in the art for a power window safety device that properly senses unsafe obstructions, but is not erroneously actuated by other, non-safety related operational conditions.
The present invention provides a vehicular power window safety device adapted to recognize an object as being stuck only when the object makes contact with a weather strip mounted at the upper portion of the door frame to cause the weather strip to become deformed, thereby preventing erroneous operation of the window glass.
In accordance with an embodiment of the present invention, a motor generates the driving force for lifting and lowering a window glass. A weather strip is mounted at the upper portion of the door frame and includes a sensor in which the electric resistance is changed by pressure exerted by an object stuck between the weather strip and the window glass due to the lifting of the window glass. A controller controls the motor in response to signals supplied from the sensor.
In an alternative embodiment, a safety device is provided for a vehicular power window including a window glass in a door frame raised and lowered by a motor, wherein the window glass follows a path defined by channels. In the safety device of this alternative, a deformable weather strip is mounted along an upper region of the door frame in a location to be contacted by the raised window glass. A sensor disposed in the weather strip is configured to generate a signal in response to excessive pressure applied by an object caught between the door frame and window glass. In a preferred embodiment, the signal is a change in resistance. A motor controller communicating with the sensor stops operation of the motor in response to the signals from the sensor. Preferably, the controller is programmed to also reverse operation of the motor in response to the sensor signals.
In a further preferred embodiment, the sensor comprises an elongate member in which electrical resistance changes in response to applied pressure. Thus, the sensor signal preferably represents changed resistance. The weather strip is also preferably configured and dimensioned such that the sensor is disposed interiorly from the window glass path. In such an embodiment the weather strip further defines a sealing member extending towards and intersecting the window glass path, whereby a tight seal is provided with the weather strip when the window glass is fully raised without obstruction. Preferably, the sealing member is provided with a low friction material along a surface adapted to contact the window glass.